[Bug tree-optimization/19624] New: PRE pessimizes ivopts

["rguenth at tat dot physik dot uni-tuebingen dot de" <gcc-bugzilla at gcc dot gnu dot org>]

The attached testcase is pessimized by PRE.  Be sure to get tree-level complete
loop unrolling enabled, f.i. with -O2 -funroll-loops with current mainline.

With PRE, a lot less computations are hoisted out of the inner loop.  Note this
is not a regression to 3.4, which is not able to decompose Loc<Dim> appropriately
or avoid instantiating temporary objects of this type.

-- 
           Summary: PRE pessimizes ivopts
           Product: gcc
           Version: 4.0.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: tree-optimization
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: rguenth at tat dot physik dot uni-tuebingen dot de
                CC: gcc-bugs at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19624